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摘要
Physico-chemical constituents of Gloriosa superba gum exudate were analyzed using recommended chemical methods. Results obtained from FT-IR study indicated the presence of functional groups that are typical for polysaccharides. Gas chromatography-mass spectrometry spectrum of the gum revealed the presence of 1-piperoylp, 1-penta-decarboxylic acid, 9-octadecenoic acid, and stigmasta-5,22-dien-3-ol. Based on its chemical constituents, corrosion inhibition potentials of various concentrations of the gum were investigated using FT-IR and gravimetric methods. The results obtained showed that Gloriosa superba gum is an inhibitor for the corrosion of Al in solution of HCl. The initial mechanism for the inhibition of Al corrosion by Gloriosa superba gum was found to be physiosorption and was succeeded by chemisorption. Although the Langmuir adsorption model supported the adsorption characteristics of the gum, the existence of interaction between the inhibitor particles was confirmed by the fitness of Flory-Huggins, Parsons, and Volmer adsorption isotherms. Analysis of El-Awady et al. kinetic isotherm revealed the formation of multiple layers of inhibitor on the surface of Al. The adsorption strength of the inhibitor was also found to increase with increasing temperature. Data obtained from the application of the Gibb-Helmholtz equation and Bockris-Swinkle adsorption model reflected spontaneous adsorption of the gum on the Al surface through chemisorption. From quantum chemical studies, it was found that the adsorption of the gum on the Al surface is facilitated by the presence of amide and hydroxyl functional groups in stigmasta-5,22-dien-3-ol and 1-piperoylp respectively.
- 出版日期2014
